Clear cell adult rhabdomyoma—a rare variant of an unusual tumour

Adult rhabdomyoma is an uncommon benign mesenchymal neoplasm that most often occurs in the head and neck. We present a 70 year-old male with a swelling on the floor of the mouth. Subsequent excision of the tumor revealed a hitherto undescribed morphological variant of this tumor that features a predominance of clear cells, which on light microscopy may mimic other other clear cell tumours of the head and neck region. We perform an in-depth analysis of the morphological and immunohistochemical features of this tumor, as well as discuss pitfalls in the diagnosis of this tumor and its differential diagnosis in the head and neck region.